I've been a little bit obssessed lately with the Bangel/Fuffy/Spuffy continuum, and what it indicates about the way the show is received. There is a distinct gap between how Buffy's main love interests are perceived in fandom .vs. canon. Buffy clearly has three major love interests across the show - Angel, Spike, and Riley. But the fans see it differently. There are three clear favoured characters to ship with Buffy - Angel, Spike, and Faith. Faith is the clear third here, but she is still well ahead of any other character, and certainly ahead of of Riley, who is nonexistent in shipping discussions. When comparison posts collating Buffy's love interest patterns appear, they so often include Faith, but do not include Riley.
I think this is quite revealing. And not because of the relative strengths of Fuffy or Briley - that's not actually important here. It's revealing for what it tells us about each character and their role in the show.
Riley is defined by his opposition to Buffy's other love interests. This is intentional - he is the "normal relationship" that Angel broke up with Buffy to allow her to have. She states explicitly that this was his intended role in her eyes. Much of her romantic arc in S4 is about moving past her relationship with Angel and accepting that not all her romances are going to be like that, for good (she won't be left alone in bed by him) and bad (she won't have the fire/passion that she craves). He is the anti-Angel, and where his scenes parallel Angel's, it is to show his difference from him.
And then moving into S5, his role shifts. The writers clearly realise that his character isn't working as expected, and that the Buffy/Riley romance is not gaining any traction with the audience. They move Spike into the role of love interest and start seriously building up Buffy/Spike. So therefore Riley becomes positioned as the anti-Spike. He is the guy who can't satisfy Buffy's desires - as opposed to Spike who as her shadow self implicitly can, and Spike will repeatedly tell them both this. He is the guy who Buffy doesn't open up to or cry around, while Spike is the guy that she does. He is the guy who cheats on Buffy and blames her emotional unavailability, while Spike is the guy who is cheated on and has his emotional unavailability blamed. In S6 when he returns, he again stands in as the apparent good, healthy romantic partner that Spike is not. Riley becomes defined by not being Spike.
Faith, on the other hand, is constructed with intentional similarity to Buffy's other love interests. Her original arc in S3 is designed as a repeat of Angel's in S2, as I and others have gone into in details plenty of times before. Like Angel, she becomes close to Buffy early on, and represents someone that could draw Buffy away from her destiny/metaphorical adulthood. Her turn into evil and eventual fate being kissed and killed in the finale mirors Angel exactly. There are a dozen other little moments throughout the season that draw more parallels. She even shares the commonality of having an ironic religion-related name (Angel being an unholy demon, Faith being someone totally lacking in any). Whether or not you see the Faith/Buffy dynamic as romantic or not, this is undeniable - Faith is Angel come again.
Faith is of course also designed as Buffy's shadow self, representative of her repressed desires and darker side. And while I would argue that she owns this role for the entire series, on a practical level she can't perform it when she's not on the show anymore. So it is Spike that picks up the mantle after her exit. And Spike and Faith both perform this role in very similar ways, in a way that distinctly differs from Buffy's other shadow self (Cordelia). They attempt to actively goad Buffy into embracing their darker side, and will explicitly tell her what she wants (which Buffy will deny but then go on to clearly confirm their truth). In both cases, it is also tied up with their own projection and desires. They both also do a lot to link Buffy's dark side to sexuality and death. Spike is in many ways Faith come again. This ends up being reflected back again in S7, when Faith and Spike become mirrored as people who follow Buffy instinctively, who stick up for her when others don't, and who are the only other people Buffy really trusts by the end.
And then there are all the ways in which Angel/Faith/Spike make a clear common trio between them. They all fit the "bad boy/girl" archetype. They all start off with a belligerent relationship to Buffy. They are all at some point villains, even the Big Bad. They all end the series as redeemed sinners who are trying to be better people than they once were. They are all supernatural warriors who are defined by being one or two of a kind. They all look great in leather. None of these apply to Riley.
So of course when it comes to grouping the love interests, of course Faith gets included in the paralllels posts and Riley doesn't. It's not just because Faith/Fuffy is more popular than Riley/Briley. It's because, by design of the show, Faith fits alongside Angel and Spike, and is deliberately positioned as their equal in many ways, while Riley is intentionally written to be their opposite and unequal comparison.
